1. Field of the Invention
The present invention relates to a technique for recovering from a fault of a Peripheral Component Interconnect (PCI) bus, and particularly to a technique for a Basic Input/Output System (BIOS) to recover from a PCI bus fault by utilizing a hot plug function that is provided in an Operating System (OS) for each PCI card.
2. Description of the Related Art
There is known a computer device that closes (shuts down) a PCI bus when a fault occurs on the PCI bus. Here, most PCI bus faults are intermittent ones. Hence, in many cases, the closed (shut-down) PCI bus becomes usable when the computer device is rebooted. However, in this way, the computer device has to be rebooted: the problem here is that fault-tolerant operation cannot be realized.
As a computer device that overcomes this problem, Unexamined Japanese Patent Application KOKAI Publication No. 2002-366375 (hereinafter identified as “Patent Literature 1”) discloses a computer device that needs not be stopped (needs not be turned off) to replace an I/O card (or a peripheral device) that has caused a fault. This computer device has two OSes, namely, a main OS and a sub OS. When an I/O card connected to the device via a PCI bus or the like and controlled by the main OS gets in fault, the computer device gets this I/O card in fault out of the control of the main OS and electrically disconnects it from the device itself. After the I/O card in fault is repaired or replaced with another one, the computer device electrically connects the repaired or replaced I/O card to itself. Then, the computer device checks the functioning condition of the repaired or replaced I/O card by using the sub OS, and returns the repaired or replaced I/O card to the control of the main OS if it functions normally. This computer device can realize fault-tolerant operation.
However, when determining whether a PCI bus (a PCI bus and an I/O card connected to the PCI bus) functions normally or not, it is necessary to consider the platform used by the OS (hardware on which the OS runs). In other words, the mechanism for checking the functioning condition of the PCI bus is dependent on the platform used by the OS. Therefore, a problem in determining whether a PCI bus functions normally or not by using the technique disclosed in Patent Literature 1 is that the OS has to have a built-in mechanism for checking the functioning condition of the PCI bus, which mechanism is matched to the platform used by the OS.